In consideration of stability, the battery pack including a plurality of battery cells includes a protective circuit module. The protective circuit module used in the battery pack is configured such that a printed circuit pattern is formed on an insulating substrate and a plurality of semiconductor devices and a protection circuit are attached to the printed circuit pattern. In addition, in order to sense temperatures of the battery cells, a thermistor attached to each of the battery cells is electrically connected to the protective circuit module to transmit a signal indicating the measured temperature is transmitted to the protective circuit module, thereby protecting the battery cells from over-charge or over-discharge. However, the process of electrically connecting the thermistor to the protective circuit module may increase complexity in the overall process. When the thermistor is connected to the protective circuit module, connection failure may undesirably occur. In addition, the thermistor may be broken with use of the battery pack.